An example would be this question:
I think it would be nice to have a collaborative effort to answer such a question. The scope is 24 episodes, plus an OVA, plus a movies. As long as the series is reasonably sized, it can possibly be answer through collaborative effort.
Possible problem would be low quality answers/partial answers. While it can be solved by adding a single answer and close the question, getting people to edit the answer is hard.
Even with those downsides, I think having such question would increase the value of our site.